Apparatus for fractionating hydrocarbon oils



July 3, 1934. w HOLMES ET AL 1,965,549

APPARATUS FOR FRACTIONATING HYDROCARBON OILS Filed Dec. 23, 1930 I 3 Sheets-Sheet I 3 FIG.1. 9 11 l0 W llmmlllmmm g l i! l i 7 i iaag- 7 5 z 4 L l E 2 4 I: L L M3 4L5 d a H 4 2 IN IENTORS ,4 K- W WW1 a? 13 ATTORNEY J y 1934- w. K. HOLMES El AL 1,965,549

APPARATUS FOR FRACTIONATING HYDROCARBON OILS Filed Dec. 23. 1930 3 Sheets-Sheet 2 y 1934- w. K. HOLMES ET AL 1,965,549

APPARATUS FOR FRAGTIONATING HYDROCARBQN OILS Filed Dec. 23, 1950 5 Sheets-Sheet 3 FIGS;

INV NTOR mdw 7 aka BY ATTORNEY ra rom 1,965,549 PATENT OFFICE APPARATUS FOR 1M9 FRACTIONATING HYDRO- CABBON OILS Will K. Holmes, Los Angeles, cum, and Andrew T. Dudley, Port Arthur, Ten, assignors to The Texas Company, New

tion of Delaware York, N. Y., a corpora- Application December 23, 1930, Serial No. 504,311

3 Claims. (Cl. 261-114) This invention relates to apparatus for the fractionation ofhydrocarbon oil and has particular reference to apparatus for the fractionation of hydrocarbon oil evolved from the thermal decomposition of hydrocarbon oils, in equipment which is resistent to corrosion and adapted to inhibit dehydrogenation of the oil and precipitation therefrom of carbonaceous matter.

The composite sections and elements of a fractionator bubble tray, according to the invention, may be fabricated from thin sheets or plates of chrome-iron or chrome-nickel-iron alloys, due to their extremely high tensile strength and to their resistivity towards deterioration. The walls of the vapor riser nipples and bubble caps so formed may be, for example, only about an eighth of an inch in thickness, which is very much thinner than those made heretofore from cast iron. As a result, either a correspondingly larger number of risers of the same internal diameter than those made from ordinary steel or cast iron, or else a similar number having a correspondingly larger internal diameter, may be provided in a single bubble tray of given diameter. The proportionately greater capacity and reduced weight of the component parts also produce a substantial reduction in total weight of the equipment for a given capacity.

Reference should be made to the figures of the accompanying drawings illustrating a desirable embodiment of apparatus adapted to practice the invention in which:

Figure 1 is an elevation view partly in section of a fractionator constructed in accordance with the invention.

Figure 2 is a section along the line 2-2 of Figure 1, showing a view of the assembled sections of a bubble tray.

Figure 3 is an elevation of a section of the taken on the line 3-3 of Figure 2.

Figure 4 is an elevation of a section of the tray taken on the line 4-4 of Figure 2 showing a corrugating structure.

Figure 5 is a sectional elevation through the line 5-5 of Figure 2 illustrating a method of securing a tray within the fractionator.

Figure 6 is a sectional elevation along the line 6-6 of Figure 2 showing in detail a bubble cap assembly and portions of two adjacent tray sections. 7

Figure 7 is a plan view of the upper portion of a, vapor nipple taken along the line '1-7 of Figure '6.

tray

Figure 8 is a bottom view along the line 8-8 of Figure 6 showing the manner of holding the bubble cap in place.

Figure 9 is a sectional elevation along the line 9-9 of Figure 6 illustrating the corrugated-or crimped structure of a supporting element.

Figure 10 is asectional elevation along the line 10-10 of Figure 2 illustrating a portion of an over-flow nipple and the method of securing it to the tray.

Referring to Figure 1, vapors from any suitable source, such as a still or cracking vessel, are conducted through a pipe 1, having a valve 2, to a Iractionator 3, the outer surface of which may, if desired, be heat insulated to avoid excessive cooling at the surface due to loss of heat by radiation or convection-to the surrounding atmosphere, thereby permitting more uniform control of temperature conditions within the tower.

A plurality of bubble trays 4, fabricated from a relatively thin alloy consisting predominantly of chromium and iron, as will be hereinafter described in more detail, are supported within the shell on annular supporting members 5 secured to and extending laterally from the inside of the shell. Each of the bubble trays are provided with a plurality of chrome-iron alloy conduits or riser nipples 6 through which the vapors rise and are then deflected downwards by bubble caps 7 into a pool of liquid maintained on the floor of each tray. A plurality of over-flow nipples 8 formed from the same or similar alloy material conduct the surplus liquid collecting on each tray to the next tray below.

A vapor outlet 9, having a valve 10, is provided at the top of the shell through which the final fractionated vapors may be removed for condensation and cooling or for further treatment. An inlet pipe 11, controlled by a valve 12, is also provided, preferably near the top of the shell, through which a reflux or cooling liquid may be introduced to the tower. A liquid outlet 13, in which is interposed a valve 14, is connected to the bottom of the shell to withdraw the reflux condensate or back-trap liquid from the fractionator.

Referring to Figure 2, each of the several tray! is composed of a plurality of composite sections 20, 21, 22 and 23, each being preferably of such dimensions that they may be conveniently inserted through the conventional manholes usually provided in a fractionator shell. Brackets 24 are provided, preferably at or near each juncture of a lateral and an arcuate portion of the rim of each section, as means for lifting and handling the section. v

The abutting or contiguous rib portions 30 of the tray sections, extending along the parallel sides of adjacent sectors, andhaving a downwardly extending member or portion 31 depending below the underside of the tray sections, pro vide means for clamping or firmly securing the several sections together with bolts .32 (Figure 6) and for strengthening or stiffening the assembled tray. Gasket material may be inserted between the abutting rib portions of the sections if desired in order to provide liquid-tight joints.

v'Ihe circular or arcuate portions of the rims,

when the sections are assembled together, form ,a continuous upwardly extending annular rim or wall 33 (Figure 5) in close proximity and conforming to, the circular interior of the shell. These annular rims confine pools of oil, which are maintained around the bubble caps of the several trays as illustrated in Figure 6.

While in Figure 5 a welded joint has been shown between the annular rim 33 and the bottom of the tray, it is contemplated that the tray sections and arcuate rim portions may be formed by pressing from single sheets of the thin metal thereby avoiding the necessity of employing welded joints.

Grooves or corrugations 35 are formed in the floor of the middle tray sections 21 and 22 to impart rigidity and stiffness to the assembled tray and prevent warping during service. Although lateral corrugations are shown it is contemplated that transverse corrugations may be advantageously employed. If desired, depending ribs or webs may be welded to the bottom of these sections to fulfill the purpose of the corrugations and in which case such webs may also run transversely of each section if desired.

As shown in Figure 5, the assembled tray is firmly seated on and secured to the horizontal and inwardly extending portion of the supporting members or angle iron 5, within the shell, by clips 36 and bolts 37 located at intervals in the bottom of the tray near its periphery. The inwardly extending portion of the angle iron is gripped firmly between the lower peripheral edge of the tray and the clips 36 fastened to its underside, thereby preventing the tray from being lifted from its seat due to the possible buoyant effect of large volumes of vapor flowing through the trays. The annular space between the wall of the tray and the shell of the fractionator may be packed with gasket material to prevent leakage of fluid therethrough.

comprise sections of thin tubing drawn or formed from chrome-iron alloy, may be secured to each tray by rolling and expanding their lower ends into holes provided in the floor of the tray. Each riser nipple is preferably provided with a preformed bead 40 near its lower edge to serve as a shoulder which rests upon the upper face of the floor of the tray. The nipple. beyond the bead, projects through the hole a sufilcient distance to allow a portion, during the process of rolling in, to be expanded and folded back against the under side of the tray floor thereby forming a second bead or flap 41 which looks and rigidly secures the riser nipple in its proper position.

A cross member or anchor strap 45 (Figures 6 and 7) is secured within the upper portion of the nipple substantially flush with its top, preferably by spottvelding. This strap is adapted to be engaged by a hook 46, the upper and threaded end of which projects through a hole in the then foldingdown the clipped portions. The

. three folded segments are preferably crimped at 52 (Figures 6 and 9) to make them conform to the circular risers 6 and to cause them to spring tightly against the walls of the risers. Each of the three-points or supporting pieces are provided with notches 53 which overlie or engage the upper edge or periphery of the riser nipple and support the bubble cap a suitable distance above the top of the riser nipple, as well as keep the cap centered with respect to the axis of the nipple.

The overflow nipples 8 (Figure-l0) comprise preferably sections of tubing formed from chromium-containing alloy or stainless steel having flange-like collars 55 secured about and at a suitable distance from the upper end. The lower portions of these overflow nipples project through holes provided in the floor of the tray and depend therefrom by the collars which seat on the floor of the tray section. If desired, sutiable circular gaskets may be inserted between the lower faces of the collars and the upper surface of the tray, the collars being rigidly fastened to the floor of the tray bytwo or more bolts 58. The top of each overflow nipple when in position extends a sufiicient distance above the floor of the tray to maintain a pool of liquid of desired depth thereon in which the depending rims or skirts of the bubble caps are submerged as in conventional practice.

All of these overflow nipples are preferably located in the outer section 20 as shown in Figure 2, and by interchanging the relative positions of ,the sections 20 and 23 on succeeding trays, the overflow nipples on one tray are thus located diametrically opposite to those on the next tray. I Thus, the reflux condensate must travel entirely across each tray in passing down the fractionator thereby effecting a more nearly uniform state of 115 equilibrium between the rising vapor and the dej scending liquid. The vapor riser nipples 6 (Figure 6), which Obviously, many modifications and variations of the invention, as hereinbefore set forth, may

be made without departing from the spirit and strap extending across the inside of said nipple,

a supporting lug positioned on top of said nipple, a bubble cap supported by said lug and a hook engaging said strap and having an end engaging said cap thereby serving rigidly to hold said cap against said lug.

3. A fractionating element comprising a sup- 14o porting plate having an opening therein, a vapor riser fixed in said opening by beads formed on said riser at each side of said plate, means for fastening a bubble cap directly to said riser and supports cooperating with the end of said riser to hold the cap asuitable vertical distance therefrom.

WILL K. HOLMES. ANDREW T. -DUDLEY. 

